Is ${781292}$ divisible by $4$ ?
Solution: A number is divisible by $4$ if the last two digits are divisible by $4$ . [ Why? We can rewrite the number as a multiple of $100$ plus the last two digits: $ \gray{7812} {92} = \gray{7812} \gray{00} + {92} $ Because $781200$ is a multiple of $100$ , it is also a multiple of $4$ So as long as the value of the last two digits, ${92}$ , is divisible by $4$ , the original number must also be divisible by $4$ Is the value of the last two digits, $92$ , divisible by $4$ Yes, ${92 \div 4 = 23}$, so $781292$ must also be divisible by $4$.